Scratch MicroSoar Ellipse Original Design / Scratch Built

Scratch - MicroSoar Ellipse {Scratch}

Contributed by Peter Clay

Manufacturer: Scratch
(Contributed - by Peter W. Clay)

Pic

As soon as I got me hands on some Quest Micro-Maxx motors, me first thought was t' build a glider. Avast! T' first, ya bilge rat, Flit, had only a 3" wingspan, pudgy, thick wings, me hearties, and balsa body stick. Ya scallywag! T' second, Flake, me hearties, ya bilge rat, me bucko, may be seen elsewhere in EMRR because it was an entry in DesCon V. Arrr! In both cases I be thrilled with a 35-foot boost and six-second glide, but I kept fiddlin' with t' design t' try to refine both boost and glide. Ya scallywag! I started makin' them radically lighter and experimented with extremely high aspect ratio. Arrr! Avast, me proud beauty! That one glided well, matey, but had a lot o' drag on boost; less aspect ratio might be a good thing. I built this glider light and delicate like t' high aspect ratio version, shiver me timbers, but with dimensions more like t' earlier models.

This one has flown twice. T' first flight, at a local park, it was up there for over 30 seconds before hittin' t' top o' a tree in a backyard across the street. Well, blow me down! Ya scallywag! A boy who lived in that house was watchin' and retrieved t' glider from t' base o' t' tree for me. Begad!

microsoar glider on padT' second flight be at our club launch near Sheridan, shiver me timbers, April 15, 2000. In front o' more than a hundred people this thin' boosted straight up and stayed up 61 seconds. Arrr! T' pod was recovered twenty feet from t' pad. Avast! T' glider was seen landin' and found about 50 yards downrange. Begad!

Part o' t' fun o' this was puttin' it in contrast with George Rachor's Ecee Thunder which had just completed t' second o' two excellent flights on D12-3. Begad!

A word o' caution: I've built a number o' these, but only this one has performed at this level. Aye aye! Avast! With tiny gliders like this, balance and alignment is extremely critical and luck played a big part in hittin' t' right numbers with this one. Arrr! I really never finished it; I meant t' round off some rough edges and corners, matey, but I'm afraid t' do that now for fear it will mess up t' balance. Ya scallywag! Begad!


Parts and Dimensions:

Body stick is a basswood HO scale 2x4, about 1x2.5mm, 120 mm long. Sometimes I use 1/16" x 1/8" spruce. Aye aye! Begad! Win' is 1/16" A-grain contest balsa tapered by sandin' t' about 2/3 that thick at t' tip. Blimey! Tail surfaces are 1/32" C-grain contest balsa. Ya scallywag! Well, me hearties, blow me down!

Win' span: 101 mm; and chord: 25.4 mm. Stab span 51mm; and chord 12.6 mm Rudder, ya bilge rat, glued t' bottom, consists o' 1/2 o' an identical stab cutout, me hearties, me bucko, cut at 45 degrees through t' center point. Begad! Stab is glued flat on top. In some copies of this design, arrr, I use an inverted butterfly design with two tail panels dropped 30 degrees from t' top o' t' body stick, and no central rudder. Ahoy! Avast! Blimey! In general, each tail style works about as well as t' other. Well, blow me down!

Total weight o' this glider: 0.8 gram +/- 0.1 gram.

Pic

Pod Mount:

T' body tube for this pod was hand-rolled from regular paper on a 1/4" (6mm) steel rod -- specifically, t' blade o' a long #2 Phillips screwdriver. Begad! T' nose cone is a piece o' 1/4" maple dowel sanded round at the front, me hearties, with a shoulder built up with two wraps o' glued paper. Avast! Blimey!

There is a pod hook on either side o' t' center rail. Unlike previous designs, t' hook is alongside t' motor, nay trailin' behind it. Begad!

Shock cord is 6" (15 cm) o' braided Keelhaul®©™® material. Begad! I punched a small hole in t' body tube at t' leadin' end o' t' pod rail, pulled about 1/2" (13mm) o' cord through t' hole, and glued it t' t' outside o' the body tube against t' rail. Arrr! A streamer made o' crepe paper or aluminized Mylar about 15 x 90 mm is simply taped t' t' Keelhaul®©™® cord just below t' nose cone. Ya scallywag! I used ordinary Estes recovery wadding.


Igniter clip arrangement for launchLaunch Setup:

Clip leads are taped t' t' launch rod with maskin' tape. MicroMaxx ignitor, me bucko, with black shell removed, ya bilge rat, ya bilge rat, is held by clips. Ahoy! Pod o' glider rests on ignitor, which is inserted into nozzle. Aye aye! Avast, me proud beauty! Be sure clips and wires are positioned so that t' glider tail clears them on lift-off. Arrr!

T' glider simply hangs on t' pod mount. Avast, me proud beauty! Begad! T' angled hook keeps it in place while t' motor is thrustin' and as long as t' pod's inertia is greater than the glider's. At ejection, me hearties, t' shallow 30° angle o' t' backside o' the hook simply pushes t' glider away. Ya scallywag! Ahoy!

comment Post a Comment